In the movie, when they finally go up to space, there is a number of explosions but if I'm not mistaken sound is created my sound waves which move around air particles, and well there is no air in space, so how could there be noise when something was blown up?

True, sound waves do mot exist in space. However, this is a movie. And in 99% of space movies there is a conscious, deliberate decision by the movie makers to add sound to the scenes for dramatic effect. As such, this isn't a slip up.